UHF tuner stop mechanism

ABSTRACT

A limit stop assembly for use with a tuning mechanism in a TV receiver or the like uses a pawl-lug assembly to effectuate the stop function. A rotatable disc is provided which is driven by the rotation of the coarse tuning shaft of the assembly. A pawl is movable by a cam on the disc between an inner position wherein it engages the cam on the disc and an outer position where it is disengaged from the cam. A rotatable stop lug is operably connected to the disc so as to be driven thereby. The stop lug has an extended portion located radially outwardly from the pawl when the pawl is in the inner position and normally out of the path of the movement of the pawl. However, the stop lug is movable to intersect the path of movement of the pawl and therefore prevents the pawl from moving to its outer position. This prevents further rotation of the disc and therefore the coarse tuning shaft. The stop function may, if desired, occur only after a predetermined number of revolutions of the assembly have been carried out. To effectuate this, the stop lug may advantageously be associated with one of the indicators of a digital indication system.

United States Patent 1191 Newberry l l June 24, 1975 [s41 UHF TUNER s roi MECHANiSM- f [75] inventor: Meigs Newberry, East Longmeadow, Mass. Y

{73] Assignee: Generalinstrument Corporation,

Clifton, NJ. 1

[22] Filed: .Ian. 9, 1974 [211 App]. No.: 432,048

Related US. Application Data [63] Continuation-in-part-of Ser. No. 386,839. Aug. 8.

l 973, abandoned.

52 us. Cl. 14110.2; 74/lO-R:'74/10.i s; 74/10.4 S [5 1] int. Cl. F16h 35/18 [58] Field of Search 74/l0.2, 10 R, 10.1 S; 74/10.4 S, 10.27, 10.54; 334/48 [56] References Cited UNITED STATES PATENTS 1616.299 11/1952 Unk et a1. 74/1112 2.942.482 6/l960 Liggett et a1. 74/104 5 3,046.8l0 7/1962 McCouch 74/102 3.333.477 8/1967 Denkowski 74/102 3.364.753 1/1968 Bidiack. 74110.4 S 3.434356 3/1969 Weiss 74/102 3.788.152 1/1974 Miner 74/10.1 S

I I Primed/Livamihe'r-Samuei Scott I Assistant Examiner-Randall Heald 511 ABSTRACT A limit stop assembly for use with a tuning mechanism 'in a TVreceiver or the like uses a pawl-lug assembly ,to effectuate the stop function. A rotatable disc is provided which is driven by the rotation of the coarse tuning shaft of the assembly. A pawl is movable by a cam on the disc between an inner position wherein it engages the c'am on the disc and an outer position where it is disengaged from the cam. A rotatable sto lug is operably connected to' thedisc so as to be driven thereby. The s'to plug has an extended portion located radially outwardly from the pawl when the pawl is in the inner position and normally out of the path of the movement of the pawL- However, the stop lug is mov able tointersect the path of movement of the pawl and'therefore prevents thefpawl from moving to its outerposition. This prevents further rotation of the disc and. therefore the coarse tuning shaft. The stop function may, if desired, occur only after a predeter- Tmined number of revolutions of the assembly have been carried out. To effectuate this, the stop lug may advantageously be associated with one of the indicators of a digital indication system.

29 Claims, 7 Drawing Figures uttr "runes sroPMectt'ANtsM g This application is a continuation-in-part of'm y pending application Ser. No. 386,839,;filed Aug. ;8;

1973, now'abandoned. v. H

The present invention r'elatestoga stop mechanism:

particularly well adapted for use injconjunctionwith a2} 1 UHF detented tuning mechanism designed to to'aj large number of communication channels, althoughlnj. adaptable for g its broader aspect the stop mechanism is.

use in other environments as well.

in some of its more genet'ic as'pects,"the vention relates to the stop mechanism disclosedln U.S. f application Ser. No. ,359.$2l entitled "Stop Mechanism For .UHF Tuner Qr- IheI. Like'-Y.Lfiled-Mayll, 1973, now U.S. Pat. No. 3,839,9 1.11 and-assignedgto e instant invention is as- 1,

same assignee to which th g h I.- t;-

Tuners designed-when actuated to tune a receivingset such as a television'receiver to a preselected one of fsumefi'who doesfnot know thecause of a given malfunction but'ls only interested in the fact that the malfunction has oceu'rredlatall. as'simply a flaw in the set as a whole.'thtts reflecting directly upon the reputation of the set manufacturer and affecting the ability of the manufacturer to sell aset of his manufacture to that person in thefttt u'resl-or comparable reasons, it is essential that the mechanical tuningarrangement be able 3 beoperat'ed b'y the serw ithextreme ease and with simplicityofmanipulation. Hence, the structure ina plurality of stations or channels are well knowrtand take many forms lnsofar as the present-.invention is concerned, the precise natureof the meanslemployed I in the communications receiver itself toeffecttuning to '2 a particularreception frequency forms no partofthe present invention. What this invention is directed to is the mechanism by means of which ,a tuning element, whatever its charactenis appropriately conditioned for precise reception of a particular station or channehiand I nism by means of which the rotation of the is stopped at the opposite ends of. the tuning'spegtruniii r The invention is here-specifically disclosed inconnectire UHF band, in which thereare seventy ormore individual channels. To provide a device capable of -I to any selected one of the seventy or more" -availab le UHF channels with sufficient accuracy was toi beablei? volv'ed must besturdy andisoconstructedas to move re d ly an tl d l bi st ,Meehanicalarrangements can be, and have been, devisedcapable'of effecting step bysteptuning,from one I.Y;;' channe l toanothen-not only'within the thirteen channel VHF,.spectrum', ;but" also within the seventy channelUHEspectrum, and;these prior. art constructions meetthe above'set forth'requiremen tstto greater or lesser degreeslloweverfany design of. the prior art hadto represent avery significant compromise. Stu rdiness can be achieved at theexpense of size and weight.

' Lo cost canibefachieve d at the expense 'ofst'urdiness.

.30, more specifically. this :invention.is directedtoamecha r-ehab'mylof acmn dance J difficult than .withalarge device. At'tempts to reducesize. weight may resultjn parts which are it"nptftztt xerlysupported .or, mounted and which therefore "w'll. n, I t tton with atuner designed to efiecttuntngovertheen 35 d to ml faculty of opera may for use of greater number of parts or larger "parts-than wouldoth erwi se be the casefthtts adding to size and: cos't ijpt her;-traderoffs will; be apparent.

to distinguishin its tuning between any two adjacejnft'flq channels presents many problems, both; mechanical f 'j fifi gfb b w n from and electrical. The-public has become accustomed to step-by-step TV tuning in connection with the thirteen available channelsin the VHFband, a nd therefore exin the UHF band, and the very high precision er tuning which is required because-of the relativelyclose spac nism f iscon tinuously jrotatable and which will tuneg'throughgthe' ,UHFspectrumand thengo back. to

leha'nn'elto channelallover againrthere are mechanical andielectrical considerations.-.which appear to make sues-,mgsmn 'ement,'unfeasibleQfAccordin"l sto pectssimilartuningcapabilityinthe uttab mbutth -ti; a p

much greater number ofchannelswhiehmustbetuned the other end, -ofthe UHF, spectrum; ,Stop mechanisms ing of thosechannels, has given rise to specia lfttew In'e -s d" chanical arrangements'for the-UHEIY; tunerstfl it is important to the tuner manufacturer to produce tuners of extremely small. size and atan exceedingly low cost. Set manufacturers areaunder pressuretrom up as little space as possible. The Tv."tube ,itself re; nismsjs'eparate and distinct fromt he 'other functioning of money when a full year's sales are taken into c'onsid-h' eration.

involving'less thanja complete, rotation of thelmechani m-la' s fisasrs s ua but w en saw channelsare tobe tuned,-and hence'seyenty different posiies' veiwe deem wheel. is're'quired ifdete'nting accuracyjs not to be sacrificed l lence, multi ttilfn detent' wheelsare often em- H Played;infltheehanismsv ofsflthe typef in question. This the consumers to produce TV receiving sets which take greatly complicates thei stopfproblemljjStop mechaparts connected to those parts by means"Oi's-filw-dqwltg'earingor thelike, can be used but they add appreciably to the size andcost of the tun ing assemblies,

p, It is a prime object of 'the present invention todevist astopar'rangementfora'tuner which will achieve tht desiredf objectives ofreliabiiity, sturdiness. low cost small size. and lowweight to an optimum degree witl respe'et'to all ofsaidrequirements, andjwith a minima 1 amount-bf sacrifice .with respect toany given require mentjn order to achieve required results with respec to someother requirement.

it is a more specific object of the present invention to provide a TV tuner construction in which the stop mechanism is constituted to as large a degree n possible by parts which are otherwiserequired in the operat ing mechanism. .1 i

it is an additional object ofthepresentinverttionto devise a stop mechanism which, bylvirtue'of its'eon structlon and arrangemenucan be adaptedto'provide '11,; thejf eamgfiach' time" the disc'ro tates"360, the cam for effective stop action at given points-in the rotation: of a detent wheel while permitting that detent wheel to make a plurality of complete rotations:

it is another object of the present invention to a stop mechanismof the multi-turn type in'rwhich the stopping is effected at a particular point by cooperation with a pre-existing position indicato sotherwise re-' quired in the opcrating me'chanism.:

Yet anotherv object of the present invention is to provide a stop mechanism, particuiarlyfor'aTVtuner cone struction, in which all of the active, parts of thestop'w mechanism are sturdily and reliably mounted for'long life and sure and easyrotationfyetin which partsjtake' 'l, 'c m yu :r up a minimal amount ofspace anda'r'eofrninim'al cost A stillfurther object of the present in vention inside fine a stop mechanism, particularly for 'a TV tit here s 25 sembiy. the parts of which can be readily and inexpen devise 1 seeend embodiment a detent wheel and detent arm are also provided but do not participate in the stop function. The, stop arm and detent arm move independently'. The cam is provided on a rotatable disc which moves with the detentwheel as the tuning shaft is rotatedi-A' cam follower in the forrnof a protrusion on the Iowerextremity of the stop arm is provided to contact contacts the fprotruslon .Pmoving the stop pawl outwardly'a lf'th'e at'op'lug is in position to prevent the outa ward movement of the stop arm. the disc is prevented from further rotation and .the stop function is accompiished. in" both embodlments'itflis preferably that the sively manufactured and assembled, thereby to produce a compact and reliable device; i

in accordance with the present invention the stop function is effected by cooperation between a rotatable stop lug which is driven by the rotation of a'disc con-- of the pawl. This portion is locatedfradially outwardlyrom e paw w en e pawlis not in contact w th the, v q w vp pg mm db f mg imp au i n is him outwardly extending section 'oi' the ream. ri ever, fled when the stop lugisrotated toafpredetcrmined 'position, the extended portionof the stop luginterse'cts' the path of movement'of the pawl; thus preventing the" pawl from moving out of the way of the' carn,"thereby'pres venting any further rotation of the discii'k; v

These means are preferably designed to bring the atop lug into the stop position after the disc has made'a'predetermined number of revolutionsinaigiven direction.

The means ma .wellcom risea ortioh of-the "osition v y p P o' described' the'ape indicatorwhichisassociatedwith'therriechanisrri;Pref-lj -r .accompanying drawinga.ingwhichz rotatable disc uponwhichthe'icam is situated be a disc jwhich'isflordinarilyincorporated into an assembly without a's'to'p' mechanism} thus "limiting the number of additionalfparts necessary; inthe first embodiment it is -.theconventional detent wheel which constitutes the v earnll-lnjthesecond it maybe partofthenormaliy prozvidediehannel numeral! indicia'f mechanism which cates units? and 'the'ot'h'erpart which indicatestens". Thefte'ns part may be"used'to'posit ionthe stop lug; in-

deed} stop lugmay well be defined, as is here specifically-disclosed; bye-paramount: tens'ii'ridex itself.

Since the tens indicator will rotate only'once for several rotations-of the detcntwl'ieeh'the disc utilized to effecr,tuate:thismotionmaybeused to support the cam of the seconder'nbodiment. Thus; the'st'op mechanism can be I advantageously 'associa'tedwi th thisporti'ori'of the as s'embly inorder to iimitthehurnber of additional parts necessary; Several misnomer thedte'rit wheelmay f A5 a'. re sul t',ff only aminimal: of parts other 4 "than .those{'alrealdy required in'the tuning mechanism may}; nausea-.101accom lis t e desired stop functio'nf,"wi tii only minimal additional space being required "'ovleribowr fl ili edrdrf'the other parts of the I tuning mechanism; u

To the] aeeomplishmentfofgtlie above and to such other objects as may hereinafterappear, the'present inerably, the stop lug has two esterided portionsrotatably] If offsetfrom each other, such thattherotationj of the 'de-fl tent wheel is prevented at both of theo'ppositeiends' oft".

the channel spectrum,

in the first embodiment pawl comprises a detent arm and a stoparm m ourited,f

moves in and out of the recesses between the detenta on the wheel thus causing the stoparm to move in a 1 similar manner. When the stop iugis positioned to pre vent the stop arm from outwardrnovemengthis also prevents the detent arm from moving outward from the' recess in which it lies. This prevents furtherrotation of the detent wheel thus accomplishing the stop function.

:- clockwisefpositiont";

ventionj relates to'the structure and arrangement of a limit s'to'p'as'sembly particularly well adapted for use in .eTVtu 'r"- a's d e fln edinfthefappended claims and as ationil'tak'enitogether with the 'FlG 't,'is "a'-side' ctional viewofthe i'irstpred-embodiment foflthe present invention; v v I ,v -l-.lG.'-2isatopcross sectionalviewfof the embodiof the present invention the a I 5 Floral F ar eutaway viewtak'en along line 3-3 Frog's is a fcutaw ayfi view taiten along line 4-4 of HO. :1 i'showing the stop lug its extremecounter.

il a eimlla r tt) that OHFIG. but showing the atoplug in an intermediate position and in its extreme c'lockwlse'rpositionr,

FlG.-'6 is aside fragmented view 'of thesecond preferred 'embodiment'of the present invention; and

FIG; 7 is'a cutaway view taken-along line 7-7 of FIG. 6.

The limit stop assembly of the present invention is specificallyvdesigncdfor use in UHF'TV tuners, al-

though it may be utilized in other applications. Ho wever, the tuner mechanism itself plays no'fpart of the present invention and therefore is not illustrated. ltwill be understood, however, that the timer may'be constituted-by a'rotary variable condenser tuned transmission line or the like. provided with asha'ft-generally' desig nated A which is, in effect. theoutput shaft of the mechanism herein disclosed, rotation ofthat shaft A effecting a tuning operation. The output shaft A is dethe cam contactsth'e protrusion. If the stop lug J is in posltlon'to preventjthestop arm F from moving outwardly. no further rotation' of the disc will be possible.

signed to be rotated by a coarsetuning shaft, generally designated B. the driving mechanism generally desig-' nated C opcrubly connecting the coarse tuning shaft B to the output shaft A. The driving mechanism C includes a detent wheel, generally. designated D, which rotates as the coarse tuning shaft B is rotated and which is detent-maintained indifferent rotational positions through the cooperation with a detent arm generally designated E. Theouter surface of the detent'wheel D is defined by a plurality of recesses separated by radially outwardly projecting portions.

in the first embodiment, as seen in FIGS. 1 through This in turn will prevent further rotation of coarse tuningshaft B."

. Preferably, 'stop log] in both embodiments is ope rably connected to or forms a part of a tens indicator K. in this lnstance,"means [is designed to index indicator ,K through-a given angleeach time coarse tuning shaft B'isrotated through t'en'positions.

- ifaddition. ajtine tuningshait, generally designated operablyconnectedto shaft A in order to provide 5, the rotation of detent wheel D from one detented po- 1 sition to the next causes detent arm'E to move outfrom and then into the recesses in a substantiallyradial path as it passes over the projecting-cams interposed be.-

tween the adjacent detent wheel recesse sf'Ksdetent arm E moves, a stop arm, generally designated F, will move along with it. Detent arm' E and stop arm F 'together form ,a pawl, generally designat'ed G Detent arm E and stop arm F are both'mounted on a shaft; gener-f ally designated H, and a springis provided to urge 3 tent arm E into the recessesofdetent wheel D. Means, generally designated 1, are-provided for drivingly connecting detent wheel D to astop' lug,'gene rally designated 1. Preferably, stop lug J is provided with two for fine tuning. As will be' described in detail below, the

rotation of the. fine tuning shaft L will cause the slight rotation ofshaft A which is necessary tomore accurately select the desired frequency.

In the tlrsfembo'diment of the'present invention herelndisclosed, theftunershaft A' is journaledin support asse'mblyjo as 'by 'means of a'cup-shapcd bearing retainer "and ball bearingsl'd; The portion of support shaft A directly ftof' tl'i'e'; right of tvstairtet'- 12 is recessed at"l6,"an d thetiplloffcoarse tuning shaft B is freely received in'thatrecess thus permitting relative rotation between thecoarseftuiting shaft B and tuner shaft A. Fast oncoai'se tuning shaft Bisa collar portion 20 upon which detentyheeiii) is mounted. Detent wheel D extends outradially from portion 20 to an appreciable degree,-a'nd'has, on;, the"periphery thereof, a plurality of detent .rccesscsi scp'ajtatedbyprotruding: portions or cams. A's dcscribedhe'r'ein, detent wheel D has ten re- I ces'sedfportions thereon. Hence, forthe tuning of sevextended portions which are circumferentially offset from each other. Each of these extended portionsis lo. cated radially outwardly of the stop arm Fwhen the ,de-.; tent arm E is situated within one of the recesses on de tent wheel D but in such a position astointerfere with radially outward movement of the'stop arm Ewhenit is in registration with the stop arm F and when the'detent arm E negotiates .one of the cams of the detent wheel D. Normally, both of the extended portions 'of stop lug J are circumferentially out of registration withjf the path of stop arm F and therefore'igdo notinterfere'jwith the movement thereoff'As' lo'ng asstoparmF is free to move. the rotation of coarse B isnot: inhibited by detent arm E. However, intwof'posi'tions in," the rotation of stop lug J, one for eachextended portion thereof, an extended portion will intersectth'e path of stop arm F, thus preventing the movement thereof.

in these positions the stop lug Jpreventsstop arm F from moving outwardly thereby preventing detent arm a ire-e 2 enty 'suchias'are'p'rovided in the UHF band, thedetet'ttftirhe'el D 'v'vi ll have to make seven rotations. East on shaiti lfieach 'end ofwhich-is mounted on support 10, is detent arm'E which forms aportior't of pawl G. Detent arm Eco'mm'unicates with the periphery of detent'wheel D so thatas detent wheel D is rotated the arm will move in' and out of the recesses thereon. Detent arm 1?. is urgedlnto the recesses on detent wheel D by mcans'of a spring which provides the appropriearest; rotata lyY mounted-on a shaft 26 which exend radially getter-29. 5 normally stationary cr o at28 i mounted on] retainer- 12 and meshes lsoimeshin'gr'with'gear 24 is crown gear Sill Which islfast on" extreme right-hand portion of I tuner sh'aft A; As coarse tuning shaft'B is rotated, gear E from moving out of the recess on detent wheel D in which it is situated. This prevents the rotation of detent wheel D and hence of coarse tuning shaft B. Means I is designed such that the extended portions ofstop'lug" J intersect the path of stop arm F at bothof the opposite ends of the channel spectrum.

In the second embodiment the detent arm D and stop arm F. although mounted on the'sameshaft H, move independently. The pawl G is comprised of stoparm F I alone. The cam. instead of being one of the raised portions on wheel D, is situated on a disc which is fast on 24 revolves about shaft B. As gear 24 revolves it meshes with crown-gear 28 which is'normally stationary, thuscausing gear 24 to rotate. The rotation of gear 24 in turn causes 'crown'gear 30 to rotate thus-rotating tunershaftArln this'vitay. the rotation of coarse tuning shaftB is transferredto tuner shaft-A.

' lnjthis first embodlment'pawl G comprises two elementsi detent arms and spaced therefrom, a stop arm F. Both l ro mottnted on shaft H suchthat they move together. As detent arm B moves along its radial path inandout'o'f the recesses of detentwheel D, stop arm F moves along a corresponding radial-path which is parallel 'to but offset along the axis of shaft H from the path' of detent arm E2" 3,890,849 7 t 1 r A a Stop lug J is situated immediately adjacent stop arm sem s position to intersect this path of stop arm F F. Preferably, stop lug J is mounted on or fon'ns a part and therefore movement thereof is permitted. of tens indicator K. Stop lug J is drive'nbymcans l. as As mentioned previousiy. fine tuning shaft L is prodescribed below, thus causing tends indlcatorK to revid'ed'to lmor'e 'eceurs'telycondltion the tuner mechatnte accordingly, s nlsm such that tho desired frequency can more pre- Stop lug J is provided with a pair of extending perelse ly,,be lelected. Fine tuning shaft .L is slidably tions, 32 and 34, rotatably offsetfromi each other. On a i mountedwlthin's finetuning shaft sleeve 52 which cxeach of the extended portions 32 and 34 is mounteda, tendsfpe rpe hdicular to the surfaceof support at the finger 36 and 38, respectively, extendingperpendicular; e't't tre rn e ft'oirt 'fright as seen in thedrawings) of the asto the plane of movement of stoplug J into the plane 10 tsembiy whenlfinetuning shaft L is depressed (moved determined by the path of movement of adjacent stop towards' the left in thodrawings) by pushing dial .74 arm F. when detent arm E is situated withinfonefof the; provided for this purpose against a spring (not shown), recesses on detent wheel D, stop arm F 'is sltu'ated lnjagear 54 which forms apart thereof meshes with a gear osition radially inward of the are which fingers 36 and 56 which is rotatably mounted on shaft 58 which is in 38 define as stop' lug J is rotated when stop iug'J is in; tum'rotatably-r'nounted on support l0.-A cam 60 is fast a rotational position wherein neitherof inf- V. tersects the radial path ofjstoparrrr' lfj'fsto' not bepre've'nted from rnoving'l'radially utard'an therefore the stop func tionfwilljjnotbeinittatedEQHoW' loeatedo'nitheiperlphery-of normally stationary crown ever, when stop lug J is in a rotationai'position wherein argas-28.13am best"be seen1by;FlG;-,;the periphery either finger 36 or 38'intersects'theradial paih'qrstep fofcrown ge t 'ir 2 8 is providedsvvith afrecess 64 iniorder arm F, as shown in' FIG. 4; stop arm F will beprevented' to accommodate camI 6 0g One side of recess 64 forms from moving radially outwardyThe, prevention of the the cam follower surface62. A'se'cond recess 66 is prooutward'radial movementfof. stop armfF -ir'i'tum will 1 "vided-onjthe': surface of normally,stationary gear 28 to cause detent arm E to remain in the recess in which it faceotfnrntsdat ts one end ofspring 22.The other end of is situated thuspreventing the rotationof deten't wheel 1 spring ZZIsest's-against protrusion '68 which extends D. The preventionof the rotationgof detent' wheciD from thesurface,ofdetentarmirin this way, spring 22 will prevent the rotation of coarse 'tuni ng'shaft' B and} :1, serves to urge camfollov'ver surface 62 into communitherefore crown gear; So r-which .o'pe'rably connects c'ationiwithcarn w while'simultaneously'urging detent coarsetunin g shaft B 'totuner shaft A; in 'thislwa'y, the arm E into theyecesstes deitentlwheei D. .v stop function is provided'Stop arm 'Fli'as'jj :extende As c am" 60 lis.rotated b'y the rotation of fine tuning nose portion 41 with .an'inclined "upp r surface; shaft ho" (ally statibnary crotvrlt gear- 2 8 is rotated (a shape of stop arm'F causes itto be: underneath, emover smaiigamouh't) urging .of spring finger 36 as lug J moves in acou'ntercio'cltwise positiom, 22 ifl'helrotation of horm aily stationary crown gear 28 The body portion 43 has'a curved back to (provide?v rotates'gear fi which inlturn'fr'otates crown gear 30. clearance for stop arm F under finger 38 as stop tags, 4 (Jea'I'Q SQIis operably connected to .t'uner 'shaft A and moves in a clockwise direction. in this way' the stop this serves to condition tunershaft A to more precisely c ordanc a, he,r t iieiijerjg ar ssgfr esarraeefer arhsoj e rnunicateswitha carir follower surface 62 function will not be effectuated until the'proper time I select thefdesired frequency. A I but when it is, the relative positionsof ail'of theleles ,f"'Ihe "digital-type position indicator normally used in ments in the assembly will be vcorrected to, initiate the- V conjunction a tuner drive assembly of the type stop function. f 5:. 1 hereinf'described oomp riscs a 'funits" dial in the form Stop lug J is provided with two extended portions'3 2, of a transparent'disc 70 (which may also act as a tuning 34, so that the rotation of coarse tuningfshaft B will be knob) mounted oncoarse tuningshaft Band a tens dial limited at either endfof thechannel selection spectrum. in the forrnof a second transparent disc 72 mounted on Stop lug J has an intermediate portion 40 uponwhich tens indicator K. The discs are preferablyc'oaxial and are mounted a series of gear teeth 42 which meshwith in close prosimity toeach other. The units disc 70 has gear 44 which forms a part of means 1. Gear is totaly; indicia injthe fo'r'rn' of the zntimerals .one to ten ably mounted on shaft46 which is in-turn mountedon radiallysp'aced slongthe surface thereof..The tens disc support 10. immediately, adjacent"s ugf-f J; and 72'hasindic'la thereon radiaily spaced aroundthe sur- 7 l fithelnttmeralsjone through r. .is 'voa d r r re nsj i s m rad s lvtet s sv t ated to mesh with gear. 44; Therefore,eachtirnodisc 48 'a' 'fviewe looltingg through .ayjsta'tionary mask (not rotates, the teeth onprojec tio'n 50 will"ceusefgettlf fl ia 5 W w ll b ts qlvi only 31 rotate through a given angle.r.Th e rotatio'nof gear; 44 =-pos ed "'of, oneofthensimeraiefrrini(each'ofjthe discs. will in turn cause stop lug J to rotate.- Teeth' 4 2, gear 44 PreferablyEde'tentwheel,recesses thereon, and disc 48 are designed suchthat stop lug Jwiilj 'rotate, and means i is'designedto index ten's'jindicator K once from its extreme counterclockwisepositioniasseen in for eachgcern'plete rotation oficoarse tuning shaft 8. HO. 4) to its extreme clockwiselposition (as seen in Therefore. the viewerwill bel a'bie'to' view in succession phantom in H6. 5) each time coarse tuning shaft Bi each of the numerals representingeach of the seventy mounted fast on coarsetuningshaftpj ha f in; a protrusion 50 on thefperiphe ryi sion 50 has a pair of g'earteeth thereo wh completes seven rotations. Stop lug J will be effective channeisin the UHF: band as thelc'oarse tuning shaft B to prevent the movement of stop arm F only when stop is rotated seven times; Stop lug .l is formed such that exlug-J is in either of the extreme positions,Therefore. v a tending portions 32 and 34'arepositioned to intersect the stop mechanism will only prevent the movement of the path of stop arm F at the opposite e'nds'of the chandetent wheel D at either end of the channel spectrum. nel selection band, Therefore, the viewer will be unable in the intermediate positions in the chanrielspectrum. to turn'cosrse tuning shaft B to a frequency corresuch as shown in FIG. 5, neither of the'fin'gers 36 and spondihg to a channel lower thanthe lowest channel in QQZFFF..IS E5 Q. P9 19" 1 3" a rotates i 1 coarse tuning shaft 8 to a frequencycorrespondingtof a channelhigher than; the .highestf channcl in.theiUHF band. in this way, a stop mechanism is provided'forlim gAistopassembiy for use with a tuning mechanisns 'cdci t lcsflof ithc lil t cfiornprising a support, a

tidetiftitnihg this rdtat ably" mounted on said support r andioperablyjconnect'ed tie condition the tuner mechaiting the m'overnentpf the e'n'dsof th'e f's i'nism v; rotatableinernberfi'operably c'onnected to said channel selection band." i

The second embodiment of illustrated in FIGS. 6 and 7, wo'rksjin the same manner as the first with the following exceptiona'ln the" second embodlmenhpttwl G is comprised only of stoparm F. l0

Detent arm D does not purtlcipate in the-stop function and moves independently of stoparm-EfStop arm F is j provided with a cam follower protrusion 3 9 on its lower extremity. Disc 48 is providedwithlac am element-51 in the same plane as plane than teeth 50.

As disc 48 is rotated,'cam- 5 l.wiilicontact 39 to move stop arrnF outward. the extended portions 36 or 38 ofstop lug J is present toprevent the outward motion of stop arm F, further rotation orets aoaiseg 48 will be prevented, thuspreventing"further-rotation of coarse tuning shaft- Bjn one fdirectionsAt the other i end of the spectrum, the'same cam eli or a different cam (not shown) will prevent furtherijrotation of coarse same manner. y t As will readily be appreciated,'fthe stop functioninf the first embodiment can onlybe initiated'at the zero' t which causes the mechanism to stop. since lu g' J is connected to the tens dial K t o move therewith. and diaiK only moveswhen the-'units mechanism'is indexed from 9 to 0, the stop function can only be effectuated at this 4 the units position of thestopatitheh upper' limit.fThus, if the possible UHF'channels are numbered throughv 79, it is not possiblein the second embodiment tohave the stop at 14 and 75 because as coarse tuning shaft is rotated towardthe highett'channels; thej'ca rn"iiijtl ie.v four"'position of disc 48will-hit' protrusion 3 9 before a the cam in the fvc position on theseventh rotation of disc 48, thus stoppingthe mechanism at 74. The re verse is true for rotations of shaft 8 towards the lower channels. However, the second embodiment does PTO! vide greater versatilitythan'the tirs ti'because anyjof the. units position can be selected for stops' if both stops are to be at the same units position,'and in some cases'fdif-" made therein. it is intended to cover all of these varia-f tions and modifications which fall withinthe scope of.

the instant invention, as defined in the following claims:

I claim:

-protruslon'39but in a different l3 tuning shaft B in the otherfdirection inpreciselyqthe2 4.'.'- 'l'l t e:.-essembl y according to claim l wherein said shefi lbibeldfiven thclfcbyiandjhaving a cam thereon with,,a raised seetionfand a lowered section. a pawl movable, by 1 ssldflpamg} between an inner position wherein it engages said lowered section of said citm it nd a'nouter posltlon 'whereinlt engages said raised section I of said cam,a stop lug rotatably mounted on said sup- 'i .'ii9t lfably connected to said disc tobe rotated thereby,said lug havin'gan extended portion located radially outwardlytrom'sald pawl when the latter is in saldlnnerposltlon. normally out of the path of movement'of sald 'pawlg towarddtssaidQOuter position but said path of movement of said pawl'and preven lssid pawl from moving to its outer potapredete' edpoint in the rotation of said sition" toclaim 1 wherein said i in; shaft; Y

stop lug rotatesiaboutjt hej same axis as said coarse tun- Thejassernbly aceording to claim! wherein said stop lugiis rnouritedfon' said coarse tuning shaft.

"pawl comprisesfa detent= arm and a stop arm axially spaced from-one anotherf and operably connected so units position (i.e. 10, 20,' 3( 40 ,"-50,;6QorIJOL'ThisQi; is because it is'the'movement of the-stop lug'J to a' posi tion which prevents stop armf-F from moving outwardlyassembly-according to claim 4.wherein said rotatable,member-comprises a vdetent wheel mounted on'isidishmiar'ld fflifie dc m'is a protrusion on gsaidjwheei." i

mblyyaccoirdin g to claimd wherein said top arm moves a ng afesubstantially radial path as said deten rm;moves betweensaidginner and outer posiftions andl'whereinfsaidextended portion of said stop 9. lug"moves]in a'n' arc which intersects said radial path of said stop arm. 1' 4 t :7. Theassembly according to claim 1 wherein said pawlcomprises ast'op armmovable independently of allother-partslof said assemblyQ "-8:TheassemblyIaccording toclaim 7 further comprising lchannel indicia rneans;op e rably connected to stop lug to be driven jth'ereby and wherein said rotatable membencomprisesa drive-gear. for said stop rotatable" r t er 'hes'mere;. rtan one cam thereon.

assembly according to claini'l wherein said stop lug has extended'portions; said extended portions bein'grotatablyoffset from each other.

[1 I. The assembly according to claim 10 wherein each -ofsaide'xtended portions is movable to engage said pawland retainsame insaid'inner position.

Th assembly. according-to claim l'wherein said .gi -flgIhefasseinbly according to claim ll wherein said ferent units positions can be selectedifor each stop..; l

While two embodiments ofthe present inventionj have been herein specifically described, it will be apparent that many variations and modifications may be 7 pawl move-sar n a substantially radial path as it moves i -"-'b'etween said innera'nd'outer positions, said extended portions of said'lug travel along an are as said lug is rotated. V

5 13' Thea'sse'mbly according to claim 12 wherein said stop :lug' is -,rot ata'bie betweena first'position wherein one of-said ext'ended portions intersects the path of movement of saidpawLa second position wherein both of saidextendedportions are nonintersecting relative to said path of movement, and a third position wherein said other extended portion intersects saidpathof operable connection betweensaiddetent-wheel and said stop lug comprises a gcar an'd .whereinsaid'stop arm engages said gear to prevent the movement thereof when said pawl is in said first position.

l6. The assembly according to claim/7 wherein said rotatable member comprises a detent wheel mounted 1 is aprotrusion on on said shaft and wherein said cam said wheel. a

17. The assembly according toclaim? further com-i prising channel indicia means ope'rably'connected to said stop lug to be driven thereby and wherein'saidrotatable member comprises a drive gear for said stop lug. i

18. The assembly accordingto claim 8 wherein said v rotatable member has morethanonecam'thereomtions being rotatably offset from'each other.

intersecting the tune'r m echanism, 7'

. 21. The rnb' ly according to claim further comprising "affine tuning shaft rotatably mounted on said support. ajcam rotatably mounted on said support and operablyccnnected to said fine tuning shaft so as to be .t driven thereby, a carnfollower' mounted on said sup- 7 port" andoperably' connected .tolth'e "tuner mechanism to condition's'ame inaccordancelwith the rotation of said cam. a

22. The assembly according to claim 21 wherein said ca'm'followe'iisoperably connected to said normally stationary'fj geantorotate samei in accordance with the rotation of said 'cam' for fine tuning purposes.

23. Tlicassem'bly according to claim 22 wherein said resilient means is also active on said urge same towards said cam. 4 a

cam follower to f 24, The assemblyaccording'to claim 20 wherein said pinion gear isfrotatable about an axis perpendicular to the aid: anemia-6r said coarse tuning shaft.

. 25. The assembly according to claim 24'wherein said normally stationary gear'and said conditioning gear are crown gears'rotatable about the same axis.

a .26; The assembly accordingto claim 20 wherein said rotatable inernber comprises a'jdetent wheel mounted =25 19. The assembly according'to claim 'whereinsaid' 'onlsaidshaft'andwherein said-cam is a protrusion on g I said wheelt'fs stop lug has two extended portions,'saidextendedpor- 20. The assembly according toclaim l further com- I prising a pinion gear mounted on said coarse tuning shaft, a tuner mechanism conditioning-gear "operably connected to the tuner mechanism to condition same in accordance with the movement of said pinion gear and a normally stationary gear mounted o n-, said sup port, said conditioning gear and said normally-station- 21; The assemblyaceording' to claim 20 ns comprising channel indicia means operably. connected to said stoplug to be driven thereby and "wherein said rotatable membercomprises a drivegear for said stop lugs i- 11-1 V 1.

I 28,;The assembly according toclairn 27 wherein said rotatable-member has more than one; cam thereon.

.; f ZQQ'Th e assembly according toclaim 28 wherein said ary gear both meshing with said pinion gear such'that the rotation of said coarse tuning shaft conditions the stop lug has two. extended portio'nsisaid extended portions being rotatably offset from each other. 

1. A stop assembly for use with a tuning mechanism in a TV receiver or the like comprising a support, a coarse tuning shaft rotatably mounted on said support and operably connected to condition the tuner mechanism, a rotatable member operably connected to said shaft to be driven thereby and having a cam thereon with a raised section and a lowered section, a pawl movable by said cam between an inner position wherein it engages said lowered section of said cam and an outer position wherein it engages said raised section of said cam, a stop lug rotatably mounted on said support and operably connected to said disc to be rotated thereby, said lug having an extended portion located radially outwardly from said pawl when the latter is in said inner position, normally out of the path of movement of said pawl toward its said outer position but movable to intersect the said path of movement of said pawl and prevent said pawl from moving to its outer position at a predetermined point in the rotation of said disc.
 2. The assembly according to claim 1 wherein said stop lug rotates about the same axis as said coarse tuning shaft.
 3. The assembly according to claim 1 wherein said stop lug is mounted on said coarse tuning shaft.
 4. The assembly according to claim 1 wherein said pawl comprises a detent arm and a stop arm axially spaced from one another and operably connected so that said stop arm moves in accordance with the movement of said detent arm, said stop lug intersecting the path of movement of said stop arm.
 5. The assembly according to claim 4 wherein said rotatable member comprises a detent wheel mounted on said shaft and wherein said cam is a protrusion on said wheel.
 6. The assembly according to claim 4 wherein said stop arm moves along a substantially radial path as said detent arm moves between said inner and outer positions, and wherein said extended portion of said stop lug moves in an arc which intersects said radial path of said stop arm.
 7. The assembly according to claim 1 wherein said pawl comprises a stop arm movable independently of all other parts of said assembly.
 8. The assembly according to claim 7 further comprising channel indicia means operably connected to said stop lug to be driven thereby and wherein said Rotatable member comprises a drive gear for said stop lug.
 9. The assembly according to claim 1 wherein said rotatable member has more than one cam thereon.
 10. The assembly according to claim 1 wherein said stop lug has two extended portions, said extended portions being rotatably offset from each other.
 11. The assembly according to claim 10 wherein each of said extended portions is movable to engage said pawl and retain same in said inner position.
 12. The assembly according to claim 11 wherein said pawl moves along a substantially radial path as it moves between said inner and outer positions, said extended portions of said lug travel along an arc as said lug is rotated.
 13. The assembly according to claim 12 wherein said stop lug is rotatable between a first position wherein one of said extended portions intersects the path of movement of said pawl, a second position wherein both of said extended portions are nonintersecting relative to said path of movement, and a third position wherein said other extended portion intersects said path of movement.
 14. The assembly according to claim 13 wherein said pawl comprises a detent arm and a stop arm axially spaced from one another and operably connected so that said stop arm moves in accordance with the movement of said detent arm, said stop lug intersecting the path of movement of said stop arm.
 15. The assembly according to claim 14 wherein the operable connection between said detent wheel and said stop lug comprises a gear and wherein said stop arm engages said gear to prevent the movement thereof when said pawl is in said first position.
 16. The assembly according to claim 7 wherein said rotatable member comprises a detent wheel mounted on said shaft and wherein said cam is a protrusion on said wheel.
 17. The assembly according to claim 7 further comprising channel indicia means operably connected to said stop lug to be driven thereby and wherein said rotatable member comprises a drive gear for said stop lug.
 18. The assembly according to claim 8 wherein said rotatable member has more than one cam thereon.
 19. The assembly according to claim 7 wherein said stop lug has two extended portions, said extended portions being rotatably offset from each other.
 20. The assembly according to claim 1 further comprising a pinion gear mounted on said coarse tuning shaft, a tuner mechanism conditioning gear operably connected to the tuner mechanism to condition same in accordance with the movement of said pinion gear and a normally stationary gear mounted on said support, said conditioning gear and said normally stationary gear both meshing with said pinion gear such that the rotation of said coarse tuning shaft conditions the tuner mechanism.
 21. The assembly according to claim 20 further comprising a fine tuning shaft rotatably mounted on said support, a cam rotatably mounted on said support and operably connected to said fine tuning shaft so as to be driven thereby, a cam follower mounted on said support and operably connected to the tuner mechanism to condition same in accordance with the rotation of said cam.
 22. The assembly according to claim 21 wherein said cam follower is operably connected to said normally stationary gear to rotate same in accordance with the rotation of said cam for fine tuning purposes.
 23. The assembly according to claim 22 wherein said resilient means is also active on said cam follower to urge same towards said cam.
 24. The assembly according to claim 20 wherein said pinion gear is rotatable about an axis perpendicular to the axis of rotation of said coarse tuning shaft.
 25. The assembly according to claim 24 wherein said normally stationary gear and said conditioning gear are crown gears rotatable about the same axis.
 26. The assembly according to claim 20 wherein said rotatable member comprises a detent wheel mounted on said shaft and wherein said cam is a protrusion on said wheel.
 27. The assembly according to claim 20 further comprising channel indicia means operably connected to said stop lug to be driven thereby and wherein said rotatable member comprises a drive gear for said stop lug.
 28. The assembly according to claim 27 wherein said rotatable member has more than one cam thereon.
 29. The assembly according to claim 28 wherein said stop lug has two extended portions, said extended portions being rotatably offset from each other. 